Method of making heat exchangers



Jam@ 2% 394% R. W. Mmmm METHOD OF MAKING HEAT EXCHAIJGElI-Sv Filed Aug. 26, 193@ lill l )Il Patented June 24, 1941 METHOD F MAKING HEAT EXCHANGERS Richard W. Kritzer, Chicago, Ill., assigner to Thermek Corporation, Chicago, Ill., a corpora.-

tion of Delaware Application August 26, 1938, Serial No. 226,880

` claims.

The invention relates to heat exchangers and, in particular, is directed to a novel construction of such devices providing increased thermal eiliciency and structural strength.

In many instances, Where the exchange of heat from one uid to another is'carriecl out, it is desirable in order to promote increased thermal eilciency to make the section of the conduit through which one of the uids is conducted of other than circular section. However, since it is usual to employ pressures within the conduit, it has heretofore been diillcult to provide conduits for' this use of sumciently high strength without making them oi circular section. In the past, conduit sections of oval, rectangular, or other than circular shapes have been employed by extending stay bolts across the raxes, of the section at spaced intervals to counteract thehoop stresses in the walls of the conduit set up by the pressure of the fluid passed through it. It is obvious that such an expedient has many disadvantages. Their use is costly and requires seals, since perforation of the walls is necessary for their installation.

The object oi the invention is to provide a heat exchanger which comprises a bodycontaining a chamber through which a iluid is passed for thermal transfer and which may be of irregular cross section, but is of high strength because of integral projections extending from one wall of the chamber and bonded to the interior side of the opposing wall,

A further object of the invention is to provide a heat exchanger which comprises a body containing a chamber through which a iiuid is passed for thermal transfer and which is provided with elements of high thermal eillciency.

Other objects of the invention will appear from the detailed description.

'I'he invention consists in the several novel features which are hereinafter set forth and more particularly defined by claims at the conclusion hereof.

In the drawing: Fig. 1 is a perspective of a heat-exchanger embodying the invention. Fig. 2 is a vertical section on line 2--2 of Fig. 1. Fig. 3 is a View illustrating the body-sections before they are bonded together, Fig. 4 is a horizontal section onlined-4 of Fig. 1, Fig. 5 is a detail showing the bond formed between the tips of spines and the walls to which they are bonded. Fig. 6 is a perspective of a portion of a plate with integral spines, used in forming one of the bodysections. Fig. 7 is a detail section illustrating the manner in which the overlapping cuts are made (ci. zei-157.3)

' Fig, 8 is a section through one oi the nipples.

The invention is exemplified in a hollow heatexchanger body through whichfluld is adapted to circulate. This body is formed of plates a and b` of any suitable metal. Plate a is shaped to provide a marginal iiange a with a flat inner iace and a bulged portion a2. provide a complementary flange b' and a complementary bulged portion b2. When the margins are bonded together as hereinafter described, bulged portions a2, b2 form the walls oi a circulating chamber d for the uid. Plate a isinitially provided with sumcient wall-thickness for the formation of oblique rows of integral spines c which are gouged out of the inner face of the portion forming bulged portion u2. c are formed by overlapping inclined cuts in the wall so that the spines will be of sufficient length to bridge the chamber d and lap the inner face of the bulged portion b3 of plate b. As a result of producing the spines from overlapping cuts, each will be provided with a pointed end c'. The spines are formed on plate a while it is flat and before it has been bulged. The spines are integral with the wall of plate a and a multiplicity of them are cut therefrom. Substantially the en tire inner portion of the wall-thickness is cut into spines. As a result the spines have a high emciency in thermal exchange from the uid circulating through chamber d to the wall of the chamber; The spines provide a high ratio of exposed surface to the mass to produce eiciency. The alternating spines on each row are bent transversely in opposite directions to permit iluid to flow more, readily between them.

The plate b is shaped to form the ilange b' and the inner face of bulge b2 and the inner face of flange b are covered with a sheet of bonding material such as copper-foil, as illustrated in Fig. 4. The spines are greater in length than the spine or chamber between bulged portions a2, b2 of the plates. The plates a and b are then pressed together with the foil d' be-- tween the llanges a', b. As they are forced together, the` pointed ends c' of the spines will be bent to lap the foil, as illustrated in Fig. 5. Next the plates are clamped together and heated in a reducing atmosphere such as hydrogen, at a temperature above the melting point of the foil.

The metal of the foil ilows between the inner faces of the anges a', b and, when the assembly is cooled, secures the plates firmly together and forms a iiuid-tight seal between the plate flanges. The melted metal also, by capillary attraction,

Plate b is shaped to The spines flows around the bent portions of the spined tips c', which lap and are pressed against plate b, thus bonding the spines which are integral with plate a to the interior surface of the plate b. When the tips of the spines are thus bonded to the plate b they promote a high degree of strength in the section of the chamber, to prevent deformation of the chamber by any internal iiuid pressure. They also serve to promote intimate contact with the iiuid within the chamber, and to conduct the heat from it to and through Y the walls of the chamber with a high degree of eiiiciency.

For connecting the chamber d to inlet and outlet pipes the margins oi plates a and b are provided with cylindrical bulges i5 to t around a nipple I6. Copper-foil d is placed around the nipple so that when the plates are bonded together the nipple I6 will be bonded and sealed to the plates, and provide means for delivering and conducting uid into and out of chamber d.

The invention exemplifies a hollow heat-exchanger body which is provided with inlet and outlet connections and which has a multiplicity of spines which are integral with one wall of the circulating chamber and bonded to the oppo site wall, to achieve increased strength and high thermal eiliciency. The method thus shown oi producing the body is simple and economical and results in the formation of a strong hollow body having a high thermal exchange eciency.

Having thus described the invention, what I claim as new and desire to secure by Letters Patent is:

l. That improvement in making plates fior use in heat exchangers which comprises gouging and transversely bending spines from the face of a substantially dat plate in rows spaced from one another by longitudinally overlapping cuts so that the spines will be longer than the spaces between the rows and the roots of the spines in the rows will be substantially contiguous.

2. That improvement in making plates for use in heat exchangers which comprises gouging and transversely bending spines having tapered ends from the face of a substantially at plate in rows spaced from one another by longitudinally overlapping cuts so that the spines will be longer than the spaces between the rows and the roots of the spines in the rows will be substantially contiguous.

3. That improvement in making heat exchange conduits which comprises gouging and transversely bending spines from the face of a substantially at plate in rows spaced from one another by longitudinally overlapping cuts so that the spines will be longer than the distance between the rows and making the cuts so the roots o! the spines lin the rows will be substantially contiguous, bending the ends of the spines to conform to the confronting face of a second plate and joining the second plate to the spined plate to surround the spines and form a conduit for fluid 4. 'I'hat improvement in making heat exchange conduits which comprises gouging and transversely bending spines having tapered ends from the face of a substantially fiat plate in rows spaced from one another by longitudinally overlapping cuts so that the lspines will be longer than the distance between the rows and making the cuts so the roots of the spines in the rows will be substantially contiguous, joining a second plate to-the spined plate to surround the spines, and bonding the tapered ends of the spines to the confronting face of the second plate.

5. That improvement in making heat exchange conduits which comprises gouging and transversely bending spines having tapered ends from the face of a substantially at plate in rows spaced from one another by longitudinally overlapping cuts so that the spines will be longer than the distance between the rows and making the cuts so the roots of the spines in the rows will be substantially contiguous, bending the tapered ends of the spines to conform to the confronting face of a second plate, joining the second plate to the spined plate to surround the spines and form a conduit for fluid.

RICHARD W. KRITZER. 

